Capacitor Array Structure to Prevent Read-Induced Polarization Reversal
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Solution Overview
Problem
Existing memory technologies using ferroelectric capacitors face challenges in maintaining the polarization state during read operations, often requiring immediate re-write after reading to restore the original state.
Innovation Solution
The formation of an array of vertically-elongated capacitor electrodes with insulative rings and a capacitor insulator, allowing for the creation of a stable memory cell structure that minimizes polarization reversal during read operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ferroelectric capacitor memory cells are used, then non-volatile storage is achieved, but polarization reversal occurs during read operations requiring immediate re-write
Solution Approach 1:
The memory cell is segmented into distinct functional regions: a first capacitor electrode extending through the ferroelectric layer, a second capacitor electrode, and an insulative region positioned between them. This segmentation isolates the read operation from affecting the entire capacitor structure, preventing polarization reversal and eliminating the need for re-write operations after reading.
2Duration of action of stationary object
If ferroelectric material is used as capacitor insulator, then non-volatile memory is achieved, but the act of reading can reverse the polarization state
Solution Approach 1:
An insulative region acts as an intermediary element positioned between the first and second capacitor electrodes. This insulative region prevents direct electrical interaction that would cause polarization reversal during read operations, while still allowing the ferroelectric material to maintain its non-volatile polarization state for data storage.
3Reliability
If vertically-elongated capacitor electrodes with insulative rings are formed, then polarization reversal during read operations is reduced, but manufacturing process complexity increases
Solution Approach 1:
The vertically-elongated capacitor electrode structure serves multiple functions simultaneously: it provides the conductive path for electrical connection, defines the capacitor geometry for optimal electric field distribution, and works with the insulative rings to prevent polarization reversal. This multi-functionality reduces the need for additional separate components, thereby managing manufacturing complexity while achieving reliable polarization state stability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the non-volatility of memory cells by reducing polarization reversal during read operations, thereby improving data retention and stability in memory arrays.
Implementation Method 1
One type of non-volatile capacitor is a ferroelectric capacitor which has ferroelectric material as at least part of the insulating material. Ferroelectric materials are characterized by having two stable polarized states and thereby can comprise programmable material of a capacitor and/or memory cell. The polarization state of the ferroelectric material can be changed by application of suitable programming voltages and remains after removal of the programming voltage
Implementation Method 2
A capacitor has two electrical conductors separated by electrically insulating material. Energy as an electric field may be electrostatically stored within such material.
Data Source
AI summary
A method used in forming an array of capacitors comprises forming an array of vertically-elongated first capacitor electrodes that project vertically relative to an outer surface. An insulative ring is formed circumferentially about individual vertically-projecting portions of the first capacitor electrodes. The insulative rings about immediately-adjacent of the first capacitor electrodes in a first straight-line direction are laterally directly against one another. The insulative rings about immediately-adjacent of the first capacitor electrodes in a second straight-line direction that is angled relative to the first straight-line direction are laterally-spaced from one another. A capacitor insulator is formed over sidewalls of the first capacitor electrodes. At least one second capacitor electrode is formed over the capacitor insulator. Additional methods, including structure independent of method, are disclosed.